[Transcriptomic analysis of the ΔPaLoc mutant of Clostridioides difficile and verification of its toxicity]

Objective: Comparative analyses of wild-type Clostridioides difficile 630 (Cd630) strain and pathogenicity locus (PaLoc) knockout mutant (ΔPaLoc) by using RNA-seq technology. Analysis of differential expression of Cd630 wild-type strain and ΔPaLoc mutant strain and measurement of its cellular virulence changes. Lay the foundation for the construction of an toxin-attenuated vaccine strain against Clostridioides difficile. Methods: Analysis of Cd630 and ΔPaLoc mutant strains using high-throughput sequencing (RNA-seq). Clustering differentially expressed genes and screening differentially expressed genes by DESeq software. Further analysis of differential genes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, cytotoxicity assays of ΔPaLoc and Cd630 strains were performed in the African monkey kidney epithelial cell (Vero) and the human colonic cell (Caco-2) lines. Results: The transcriptome data showed that the ΔPaLoc mutant toxin genes tcdA and tcdB were not transcribed. Compared to the wild-type strain, CD630_36010, CD630_020910,CD630_02080 and cel genes upregulated 17.92,11.40,8.93 and 7.55 fold, respectively. Whereas the hom2 (high serine dehydrogenase), the CD630_15810 (spore-forming protein), CD630_23230 (zinc-binding dehydrogenase) and CD630_23240 (galactitol 1-phosphate 5-dehydrogenase) genes were down-regulated by 0.06, 0.075, 0.133 and 0.183 fold, respectively. The GO and KEGG enrichment analyses showed that the differentially transcribed genes in ΔPaLoc were enriched in the density-sensing system, ABC transport system, two-component system, phosphotransferase (PTS) system, and sugar metabolism pathway, as well as vancomycin resistance-related pathways. Cytotoxicity assays showed that the ΔPaLoc mutant strain lost its virulence to Vero and Caco-2 cells compared to the wild-type Cd630 strain. Conclusion: Transcriptional sequencing analysis of the Cd630 and ΔPaLoc mutant strains showed that the toxin genes were not transcribed. Those other differential genes could provide a reference for further studies on the physiological and biochemical properties of the ΔPaLoc mutant strain. Cytotoxicity assays confirmed that the ΔPaLoc mutant lost virulence to Vero and Caco-2 cells, thus laying the foundation for constructing an toxin-attenuated vaccine strain against C. difficile.

Maintenance Treatment With Low-Dose Decitabine After Allogeneic Hematopoietic Cell Transplantation in Patients With Adult Acute Lymphoblastic Leukemia

Background

Post-transplant relapse remains a principal leading cause of failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with adult acute lymphoblastic leukemia (ALL). The aim of this study was to investigate the efficacy and safety of low-dose decitabine on the prevention of adult ALL relapse after allo-HSCT.

Methods

In this prospective study, we enrolled 34 patients with ALL who underwent allo-HSCT from August 2016 to April 2020 and received low-dose decitabine maintenance treatment after transplantation. The primary objectives were cumulative incidence of relapse rate (CIR), overall survival (OS), and disease-free survival (DFS). The secondary objectives were graft-versus-host disease (GVHD) and safety.

Results

Among the enrolled 34 patients, 6 patients relapsed and 6 patients died. The 2-year CIR, OS, and DFS were 20.2, 77.5, and 73.6%, respectively. Subgroup analysis revealed the 2-year CIR, OS, and DFS rates of 12 patients with T-ALL/lymphoblastic lymphoma (LBL) were 8.3, 90, and 81.5%, respectively. None of the seven patients with T-ALL relapsed. During maintenance treatment, only one patient (2.9%) developed grade IV acute GVHD and four (11.8%) patients had severe chronic GVHD. Thirty-two patients (94.1%) developed only grade I to II myelosuppression, and two patients (5.8%) developed grade III to IV granulocytopenia.

Conclusions

Maintenance treatment with low-dose decitabine after allo-HSCT may be used as a therapeutic option to reduce relapse in patients with adult ALL, especially in patients with T-ALL. Our findings require confirmation in larger-scale controlled trials.

Clinical Trial Registration

Chinese Clinical Trials Registry, identifier ChiCTR1800014888.

NF-кB pathway genes expression in chicken erythrocytes infected with avian influenza virus subtype H9N2

1. Chicken erythrocytes in blood vessels are the most abundant circulating cells, which participate in the host's immune responses. The transcription factor nuclear factor-kappa B (NF-κB) plays a vital role in the inflammatory response following viral infections. However, the expression of the NF-κB pathway, and other immune-related genes in chicken erythrocytes infected with low pathogenic avian influenza virus (LPAIV H9N2), has not been extensively studied.2. The following study determined the interaction of LPAIV H9N2 with chicken erythrocytes using indirect immunofluorescence microscopy. This was followed by investigating myeloid differentiation primary response 88 (MyD88), C-C motif chemokine ligand 5 (CCL5), melanoma differentiation-associated protein 5 (MDA5), the inhibitor of nuclear factor-kappa B kinase subunit epsilon (IKBKE), NF-κB inhibitor alpha (NFKBIA), NF-κB inhibitor epsilon (NFKBIE), interferon-alpha (IFN-α), colony-stimulating factor 3 (CSF3) and tumour necrosis factor receptor-associated factor 6 (TRAF6) by mRNA expression using quantitative real-time PCR (qRT-PCR) at four different time intervals (0, 2, 6 and 10 h).3. There was a significant interaction between erythrocytes and LPAIV H9N2 virus. Furthermore, the mRNA expression of the NF-κB pathway and other immune-related genes were significantly up-regulated at 2 h post-infection in infected chicken erythrocytes, except for TRAF6, which were significantly downregulated. While at 0 h post-infection, IFN-α and CSF3 were significantly upregulated, whereas NFKBIA was significantly downregulated. Further expression of MDA5, CCL5 and NFKBIA was upregulated, while TRAF6 was downregulated at 6 h post-infection. In infected erythrocytes, expression of MyD88, CCL5 and IKBKE was upregulated. However, IFN-α and TRAF6 were downregulated at 10 h post-infection.4. These results give initial evidence that the NF-κB pathway, and other genes related to immunity, in chicken erythrocytes may contribute to LPAIV subtype H9N2 and induce host immune responses.

Hemostasis functions are associated with hemorrhagic transformation in non-atrial fibrillation patients: a case-control study

Background

Hemorrhagic transformation (HT) is a serious neurological complication of acute ischemic stroke (AIS) after revascularization. The majority of AIS patients do not have atrial fibrillation (AF) which could also develop into HT. In this study, we aimed to explore whether hemostasis parameters are risk factors of HT in non-AF patients.

Methods

We consecutively enrolled 285 AIS patients with HT. Meanwhile, age- and sex-matched 285 AIS patients without HT were included. The diagnosis of HT was determined by brain CT or MRI during hospitalization. All patients were divided into two subgroups based on the presence of AF and explore the differences between the two subgroups. Blood samples were obtained within 24 h of admission, and all patients were evenly classified into three tertiles according to platelet counts (PLT) levels.

Results

In this study, we found the first PLT tertile (OR = 3.509, 95%CI = 1.268–9.711, P = 0.016) was independently associated with HT in non-AF patients, taking the third tertile as a reference. Meanwhile, we also found mean platelet volume (MPV) (OR = 0.605, 95%CI = 0.455–0.805, P = 0.001) and fibrinogen (FIB) (OR = 1.928, 95%CI = 1.346–2.760, P < 0.001) were significantly associated with HT in non-AF patients. But in AF patients, hemostasis parameters showed no significant difference. Meanwhile, we found the MPV (OR = 1.314, 95%CI = 1.032–1.675, P = 0.027) and FIB (OR = 1.298, 95%CI = 1.047–1.610, P = 0.018) were significantly associated with long-term outcomes in non-AF HT patients.

Conclusions

Low PLT, low MPV, and high FIB levels were independently associated with HT in non-AF patients. Additionally, MPV and FIB levels were significantly associated with unfavorable long-term outcomes in non-AF HT patients. Our study showed that hemostasis functions at admission may be beneficial for clinicians to recognize patients with a high risk of HT at an early stage and improve unfavorable long-term outcomes in non-AF patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02065-3.

Liver Fibrosis Is Associated With Hemorrhagic Transformation in Patients With Acute Ischemic Stroke

Background: Hemorrhagic transformation (HT) is a frequent, often asymptomatic event that occurs after acute ischemic stroke (AIS). Liver fibrosis, usually subclinical, is common and crucial in the development of liver disease. We aimed to investigate the association between liver fibrosis and HT in patients with AIS.

Methods: We performed a single-center and retrospective study. A total of 185 consecutive participants with HT and 199 age- and sex-matched stroke patients without HT were enrolled in this study. We calculated one validated fibrosis index—Fibrosis-4 (FIB-4) score—to assess the extent of liver fibrosis. HT was detected by routine CT or MRI and was radiologically classified as hemorrhagic infarction type 1 or 2 or parenchymal hematoma type 1 or 2. HT was also classified into asymptomatic or symptomatic. We used logistic regression models adjusted for previously established risk factors to assess the risks for HT.

Results: The median FIB-4 score was significantly higher among patients who developed HT than among those without HT, whereas standard hepatic assays were largely normal. Patients were assigned to groups of high FIB-4 score and low FIB-4 score based on the optimal cutoff value. Compared with the subjects in the low-FIB-4-score group, incidence of HT for the high-FIB-4-score group was significantly higher. After adjustment for potential confounders, the patients with high FIB-4 score had 3.461-fold risk of HT in AIS compared to the patients with low FIB-4 score [odds ratio, 3.461 (95% CI, 1.404–8.531)].

Conclusion: Liver fibrosis, measured by FIB-4 score, was independently associated with the risk of HT in AIS patients.

RNA-Seq reveals inflammatory mechanisms of Xiao-Ban-Xia-Tang decoction to ameliorate cisplatin-induced emesis in a rat pica model

OBJECTIVES

Xiao-Ban-Xia-Tang decoction (XBXT), an antiemetic formula in traditional Chinese medicine, has been proved to be a potential treatment for chemotherapy-induced nausea and vomiting (CINV), but the underlying mechanisms are not adequately understood. This study aimed to investigate changes in the ileum transcriptome after cisplatin and XBXT treatment and to reveal whether the antiemetic mechanisms of XBXT are related to its anti-inflammatory effect.

METHODS

The pica model was established by a single intraperitoneal injection of 6 mg/kg cisplatin in Wistar rats. Tissues from the gastric antrum and ileum were stained with hematoxylin-eosin to observe gastrointestinal tract pathological changes. Based on the differentially expressed genes (DEGs) which were altered by cisplatin and reversed by XBXT, the transcriptome data of rat ileum were analyzed by GO, KEGG, and PPI analyses. Several inflammatory DEGs were validated by RT-PCR.

RESULTS

XBXT could reduce kaolin intake up to 72 h after modeling and alleviate the inflammatory damage of gastric antrum and ileum induced by cisplatin. According to the transcriptome profile, there were 75 DEGs down-regulated by cisplatin and up-regulated by XBXT and 343 DEGs up-regulated by cisplatin and down-regulated by XBXT. XBXT could blunt the overexpression of tryptophan hydroxylase 1 (the rate-limiting enzyme of serotonin synthesis) in ileum. Enrichment analysis showed that inhibiting overexpression of several conventional inflammation pathways and pro-inflammation cytokines were related to the antiemetic effectiveness of XBXT.

CONCLUSIONS

This study implies that inhibiting inflammatory signaling pathways and synthesis of serotonin might be potential mechanisms of XBXT's antiemetic effect against CINV.

Reduced Vitamin D Levels are Associated with Stroke-Associated Pneumonia in Patients with Acute Ischemic Stroke

Background and aim

Stroke-associated pneumonia (SAP) is a common complication in patients with acute ischemic stroke (AIS). This study explored the potential relationship between serum vitamin D levels and SAP.

Methods

This study recruited 863 consecutive AIS patients. In-hospital SAP was defined as a complication that occurred after stroke, during hospitalization, that was confirmed radiographically. Serum vitamin D levels were measured within 24 hrs of admission and the patients were divided into vitamin D sufficient (>50 nmol/L), insufficient (25–50 nmol/L), and deficient (<25 nmol/L) groups.

Results

In this study, 102 (11.8%) patients were diagnosed with SAP. Compared to the patients without SAP, patients with SAP had significantly lower vitamin D levels (P = 0.023). The incidence of SAP was significantly higher in patients with vitamin D deficiency than in those with vitamin D insufficiency or sufficiency (21.2% vs 16.2% & 9.5%, P = 0.006). After adjusting for confounders, vitamin D deficiency and insufficiency were independently associated with SAP (OR = 3.034, 95% CI = 1.207–7.625, P = 0.018; OR = 1.921, 95% CI = 1.204–3.066, P = 0.006, respectively). In multiple-adjusted spline regression, vitamin D levels showed a linear association with the risk of SAP (P < 0.001 for linearity).

Conclusion

Reduced vitamin D is a potential risk factor of in-hospital SAP, which can help clinicians identify high-risk SAP patients.

Individualized Prediction Of Stroke-Associated Pneumonia For Patients With Acute Ischemic Stroke

Background

Stroke-associated pneumonia (SAP) is a serious and common complication in stroke patients.

Purpose

We aimed to develop and validate an easy-to-use model for predicting the risk of SAP in acute ischemic stroke (AIS) patients.

Patients and methods

The nomogram was established by univariate and multivariate binary logistic analyses in a training cohort of 643 AIS patients. The prediction performance was determined based on the receiver operating characteristic curve (ROC) and calibration plots in a validation cohort (N=340). Individualized clinical decision-making was conducted by weighing the net benefit in each AIS patient by decision curve analysis (DCA).

Results

Seven predictors, including age, NIHSS score on admission, atrial fibrillation, nasogastric tube intervention, mechanical ventilation, fibrinogen, and leukocyte count were incorporated to construct the nomogram model. The nomogram showed good predictive performance in ROC analysis [AUROC of 0.845 (95% CI: 0.814-0.872) in training cohort, and 0.897 (95% CI: 0.860-0.927) in validation cohort], and was superior to the A²DS², ISAN, and PANTHERIS scores. Furthermore, the calibration plots showed good agreement between actual and nomogram-predicted SAP probabilities, in both training and validation cohorts. The DCA confirmed that the SAP nomogram was clinically useful.

Conclusion

Our nomogram may provide clinicians with a simple and reliable tool for predicting SAP based on routinely available data. It may also assist clinicians with respect to individualized treatment decision-making for patients differing in risk level.

[Efficacy of thrombolytic therapy using reteplase in cases with acute ST-segment elevation myocardial infarction: results from a multicenter clinical trial]

Objective: To evaluate the efficacy and safety of intravenous thrombolytic therapy using reteplase in patients with acute ST-segment elevation myocardial infarction (STEMI). Method: A total of 73 hospitals from Henan province took part in this clinical trials during October 2012 to October 2014, 1 226 cases (1 014 male (82.7%), mean age 59.0 (51.0, 66.0) years) with acute STEMI received reteplase as thrombolytic agent.Reperfusion rate was judged according to the clinical symptoms, electrocardiogram, myocardial enzymes and heart rhythm, and the rate of cardiovascular events and bleeding events during hospitalization was also observed.Bleeding events were evaluated with global utilization of streptokinase and tissues plasminogen activator for occluded coronary arteries (GUSTO) criteria.Subgroup analysis was performed to compare the effects of various thrombolysis timing (time from onset to thrombolysis≤6 h or 6-12 h) on reperfusion rate, cardiovascular events and bleeding events rate. Results: The reperfusion rate was 89.3% (1 089/1 219) at 120 minutes after the thrombolysis, average recanalization time was (59.96±26.86) minutes.The reperfusion rate of ≤6 h thrombolysis group was significantly higher than in 6-12 hours group (90.3% (988/1094) vs. 80.8% (101/125), P=0.001), while in-hospital mortality (2.6%(28/1 094) and 0.8% (1/125), P=0.352) and rate of bleeding (5.9%(64/1 094) and 5.6%(7/125), P=0.910) were similar between the two groups. The total in-hospital mortality after thrombolysis was 2.4% (29/1219), which was significantly higher in failed recanalization group than in recanalization group (10.8%(14/130) vs. 1.4%(15/1089), P< 0.001). The total rate of bleeding after thrombolysis was 5.8% (71/1219), there were 3 severe bleeding cases according to GUSTO classification (0.2%), all of them were cerebral hemorrhage, and 2 out of 3 cases died. Conclusions: Reteplase use is related to high recanalization rate and low cardiovascular events and bleeding rate and our results thus show that reteplase is a safe and effective thrombolytic agent for STEMI patients.

Novel polymorphic microsatellite markers for Bellamya and their application in population genetics of three species

Bellamya is a widely distributed freshwater snail genus in China; however, its genetic diversity is completely unknown. Sixty-five novel microsatellite loci were isolated and characterized from a microsatellite-enriched library of Bellamya aeruginosa genomic DNA. Most of the 65 loci were successfully amplified. We found high polymorphic information content values for these loci, ranging from 0.235 to 0.892. There were 3 to 12 alleles per locus, and the HE and HO varied from 0.425 to 0.953 and 0.026 to 1.000, respectively. Fifteen loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni's correction. All 65 SSR markers were tested in an additional five Bellamya species, and 96.9% of the 325 locus/taxon combinations tested resulted in cross-species amplification. Seven polymorphic microsatellite markers were randomly selected for comparison among nine populations of three species. All populations had moderate to high genetic diversity. In genetic distance-based cluster analysis, the populations of B. aeruginosa and B. dispiralis formed species-based clusters, whereas populations of B. angularia did not. The three examined Bellamya species could be differentiated using SSR markers. These microsatellite loci should be useful for genetic diversity analysis, analysis of phylogenetic relationship, and species delimitation of Bellamya.

Simultaneous directional emissions of multiple quantum emitters with cross plasmonic antenna

We introduce a cross plasmonic antenna (CPA) for the system of multiple quantum emitters (QEs) with different emission wavelengths, where the excitation light scattering and emission fluorescence of different QEs are spatially separated in four different directions. By considering the CPA as oscillating dipoles, this phenomenon is attributed to the phase differences between them. The enhancement for QEs are very strong in correponding directions. In addition, the fluorescence is strongly polarized. By adding a silver plate as substrate, the directivity can be further tuned in the whole upper half space. Our result shows that the CPA is promising for realization of an efficient, directional and strongly polarized nano-scale light source, which will have potential application in Nano-Optics.

Mode division multiplexing in a polymer-loaded plasmonic planar waveguide

A mode division multiplexer (MDM) based on in-plane diffractions is experimentally demonstrated in a polymer-loaded plasmonic planar waveguide. Three guided modes (TM₁, TE₁, and TM₂) were well demultiplexed by a focusing design with a focal length of about 40 μm, which are clearly distinguished by the polarization control. The experimental results well reproduced the theoretical design and calculation. Moreover, the demultiplexed focal spots directly reflect the different modes, by which a mode diagram of the dielectric-loaded planar waveguide was vividly mapped out by varying the polymer layer thickness. In this regard, the proposed device may not only serve as a MDM for the integrated optics but can also provide a new strategy in analyzing the guided modes.

Efficient second-harmonic generation in nonlinear plasmonic waveguide

We theoretically studied a nonlinear optical process in a hybrid plasmonic waveguide composed of a nonlinear dielectric waveguide and a metal film with a separation of a thin air gap. Owing to the hybridization effect of guided mode and surface plasmon polariton mode, this particular waveguide is able to confine the optical-field in a deep subwavelength scale together with low propagation loss. Based on this, efficient second-harmonic generations (SHG) were revealed at the fundamental wavelength of λ=1.55 μm with good field confinement. The SHG efficiency, as well as the coupling coefficient and mode area, were analyzed and discussed in detail with respect to the structural parameters.

Effect of vaccination with 3 recombinant asexual-stage malaria antigens on initial growth rates of Plasmodium falciparum in non-immune volunteers

A placebo controlled, randomised, double blind trial was conducted in human volunteers to test a mixture of three recombinant Plasmodium falciparum blood stage antigens for its ability to reduce the initial growth rates of parasites. The vaccine contained recombinant MSP2 (3D7 allele), a portion of MSP1 (190LCS.T3) and part of the RESA antigen (C terminal 771 amino acids) in the Montanide ISA 720 adjuvant (SEPPIC). Twelve volunteers received two doses of the vaccine, 6 weeks apart. The five participants in the placebo group received an equivalent volume of the adjuvant emulsion using the same schedule. Antibody responses were low, as has been reported in earlier studies with this combination, while T cell responses were stronger. All the volunteers were challenged with approximately 140 ring infected red cells of the 3D7 cloned line, 4 weeks after the second dose. Parasitaemia was determined once daily from day 4 using a sensitive and quantitative PCR assay. All the volunteers were infected and were treated on day 8, before any developed symptoms. There was no significant difference in initial parasite growth rates between the verum and placebo groups, nor was there any significant correlation between parasite growth rates and any of the measured immunological responses. These results suggest that the formulation tested in this trial did not generate immune responses that were strong enough to reduce parasite growth in naive volunteers.